Method of making a windshield and leaf screen assembly

ABSTRACT

A method of forming a window assembly which includes a windshield and a gasket formed by curing a polymeric gasket material in situ on the windshield to encapsulate a marginal peripheral edge thereof and form an integral leaf screen and mounting tab. The gasket is formed in a mold with the windshield typically by a reaction injection molding process. The gasket-forming cavities in the mold can be separated by removable plugs and be connected to multiple inlet means for separately filling the cavities. The gasket, leaf screen and mounting tab can be formed of one material, or the leaf screen and tab can be formed of a different material then the gasket.

This is a division of application Ser. No. 06/812,727 filed Dec. 23,1985, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates generally to a window assembly and to aprocess for producing the assembly, and more particularly to awindshield assembly for a vehicle including a glass viewing area havinga gasket formed along at least one edge thereof including an integralleaf screen.

Initially, fixed window assemblies for vehicles were comprised of aplurality of elements including adhesive sealants applied around themarginal edges of the window, suitable mechanical fasteners such asmetal clips, and exterior decorative trim strips disposed to cover thejunction between the marginal edges of the window and the adjacentportions of the vehicle frame. Such window structures were costly,especially from a labor standpoint, since it was necessary to assemblethe individual elements along the vehicle assembly line.

Subsequently, in an endeavor to improve the above window structure,unitary window assemblies of the type illustrated in U.S. Pat. No.4,072,340 were developed. These assemblies included a sheet of glass, anadjacent frame, and a casing or gasket of molded material, such aspolyvinylchloride, extending between the frame and the peripheral edgeof the window to hold the sheet of glass and the frame together.Fasteners were provided at spaced locations along the frame such thatthe entire assembly could be guided into location over the opening in avehicle body as a unit. Other types of unitary window assemblies aredisclosed in U.S. Pat. Nos. 3,759,004 and 4,364,595. While such unitarywindow structures greatly reduce the time required to mount the windowassembly in the associated vehicle, such structures are relativelycostly, since the individual components required to produce each windowassembly generally must be manually assembled.

SUMMARY OF THE INVENTION

The present invention relates to a window assembly and a method ofmaking the same including a mold structure for forming a gasket around apredetermined portion of a frangible sheet or sheets of transparentmaterial, such as glass, to produce a unitary window assembly. In thepreferred embodiment of the invention, the gasket is formed bypolymerizing and curing a gasket forming material in situ on the glasssheet to encapsulate the marginal peripheral edge portion thereof. Thegasket is typically formed by a reaction injection molding process.

More specifically, the mold structure includes at least two cooperatingmold sections each having a recessed portion formed therein in facingrelationship to one another. The recessed portions cooperate to define asheet receiving chamber for receiving a vehicle windshield structure,for example a single sheet of heat strengthened glass or, as is moreoften the case a laminated assembly of two glass sheets integrallybonded together through an interposed layer of plastic, e.g., polyvinylbutyral. A compressible seal means is positioned about at least aportion of the periphery of the chamber and functions to resilientlysupport the windshield within the chamber. Each mold section includes ametallic main body portion, and the seal means maintains the windshieldin spaced-apart relationship with the main body portions of the moldsections to prevent any glass-to-metal contact between the glass and themetallic mold sections.

Also, the seal means cooperates with predetermined portions of thewindshield and the mold sections for defining a gasket cavity having aconfiguration corresponding to the gasket to be formed on thewindshield. At least portions of the facing surfaces of mold sectionsdisposed outwardly of the gasket forming cavity are in metal-to-metalcontact with one another. This enables the amount the seal means iscompressed and the dimensions of the gasket to be precisely controlled.Inlet means or gates are provided for introducing a flowable gasketforming material into the gasket cavity.

The window assembly also includes an integral leaf screen and locatortab which replaces the prior art separate leaf screens at the base ofthe windshield. The leaf screen is attached to the window glass by agasket portion formed at the same time and in the same manner as thesealing gaskets on the window. The gaskets and the leaf screen can beformed of different materials by use of a plug to block off one area ofthe mold while the forming material is being injected in the other areaof the mold.

BRIEF DESCRIPTION OF THE DRAWINGS

The above, as well as other advantages of the present invention, willbecome readily apparent to those skilled in the art from the followingdetailed description of a preferred embodiment when considered in thelight of the accompanying drawings, in which:

FIG. 1 is a perspective view of a window assembly according to thepresent invention;

FIG. 2 is an enlarged fragmentary sectional view of the window assemblyof FIG. 1 taken along the line 2--2 thereof;

FIG. 3 is a top plan view of a mold structure for fabricating the windowassembly of FIG. 1 according to the present invention with a portion ofthe upper half of the mold cut away;

FIG. 4 is an enlarged fragmentary sectional view of the window assemblyand mold structure of FIG. 3 taken along the line 4--4 thereof;

FIG. 5 is a top plan view of the lower half of an alternate embodimentof the mold structure in FIG. 3;

FIG. 6 is an enlarged fragmentary view of a portion of the moldstructure of FIG. 5; and

FIG. 7 is an enlarged fragmentary sectional view of the mold structureof FIG. 5 as if taken along the line 7--7 in FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT

There is shown in FIG. 1 a window assembly 10, according to the presentinvention, including a windshield 11, illustrated herein as including apair of glass sheets and an interposed layer of polyvinylbvutyraintegrally bonded to the sheets, having its peripheral edgesencapsulated by a gasket 12. The gasket 12 includes a top portion 13,side portions 14 and 15, and bottom portion 16 which portions completelyencapsulate the peripheral edges of the windshield 11. Attached to thebottom portion 16 is an integral leaf screen 17 and a locating tab means18 extends from a front edge of the leaf screen 17. The leaf screen 17replaces the prior art leaf screens which were typically formed of wiremesh, stamped steel or molded rigid plastic. These screens are utilizedto prevent debris from falling into the engine compartment between thehood and body of those vehicles having windshield wipers mounted in thatarea. In order to provide for the passage of air between the exterior ofthe vehicle and the engine compartment, a plurality of elongated slotsor apertures 19 are typically formed in the leaf screen 17.

Referring to FIGS. 1 and 2, the gasket portions 13, 14, 15 and 16completely encapsulate the peripheral edge of the windshield 11 toprovide a seal against the intrusion of fluids between the windshieldand the frame of the vehicle in which it is installed. Thus, the windowassembly 10 is typically fitted into an opening in the vehicle and thegasket 12 is secured to the vehicle with a suitable adhesive. The leafscreen 17 is formed integral with the remaining portions of the gasket12 and at the proper angle such that it fills an opening between thebody of the vehicle and the hood of the vehicle. The tab means 18 caninclude one or more apertures 20 for receiving fastening means to securethe leading edge of the leaf screen, typically to the body of thevehicle.

Referring to FIGS. 3 and 4, there is shown a mold 30 for making awindshield assembly in accordance with the present invention. The mold30 is formed of a lower section 31 and an upper section 32 (half ofwhich has been cut away along a center line 33 for illustrationpurposes). While the mold sections 31 and 32 are typically formed of ametallic material such as steel or aluminum, for example, other types ofsubstantially non-resilient, rigid material can be used. Suitable means,not shown, are provided to open and close the mold sections 31 and 32.Also, each of the mold sections 31 and 32 can be provided withpassageways (not shown) for circulating a suitable coolant through therespective mold sections.

The mold sections 31 and 32 are provided with recessed portions 34 and35 respectively in facing relationship to one another such that, whenthe mold sections are closed, the recessed portions 34 and 35 cooperateto define a windshield receiving or glass clearance chamber 36 forreceiving windshield 11 on which a gasket is to be formed. When the moldsections are open, the windshield 11 is positioned on the lower section31 so that the outer peripheral portion of the lower section 31 so thatthe outer a resilient lower seal 37 positioned within a groove 38 formedin the upper surface of the lower section 31.

After the windshield 11 is suitably positioned on the seal 37 of thelower mold section 31, the upper mold section 32 is lowered intoposition to enable the outer peripheral portions of the facing surfaces39 and 40 of the cooperating mold sections 31 and 32 respectively to beclamped together in a metal-to-metal contact, as shown in FIG. 4. Theupper mold section 32 carries a resilient upper seal 41 positioned in agroove 42 formed opposite the groove 38. The upper seal 41 cooperateswith the lower seal 37 to press yieldingly against the windshield 11 andresiliently support the windshield within the glass clearance chamber36.

The chamber 36 of the mold 30 is slightly larger than the formedwindshield 11 to avoid any glass-to-metal contact between the windshield11 and the metallic mold sections 31 and 32. However, it will beappreciated that the glass clearance chamber 36 can be formed of anyshape as long as the chamber is sufficiently large to avoid anyglass-to-metal contact between the windshield and the metallic moldsections. For example, the portions of the mold sections 31 and 32 whichare below and above the central portions of the windshield 11 can beremoved such that each mold section will be generally ring-shaped. Theseals 37 and 41 are preferably formed of a silicone rubber material andsecured within the respective grooves 38 and 42 by means of a suitableadhesive. Alternatively, the seals 37 and 41 can be releasably securedwithin the respective grooves. This can be accomplished by providing tabportions (not shown) in spaced apart locations around the respectiveseal which can be inserted and releasably held within corresponding tabreceiving apertures (not shown) formed at corresponding spaced apartlocations around the respective groove.

In addition to resiliently supporting the windshield 11 within the glassclearance chamber 36, the seals 37 and 41 cooperate with select portionsof the windshield 11, and the mold sections 31 and 32 for defining thegasket forming cavity utilized to form the gaskets 13, 14, 15 and 16.More specifically, these gasket forming cavities includes a lower cavity43 which extends completely around the outer periphery of each of thelower seal 37 and the upper seal 41 for forming the top portion 13, sideportions 14 and 15, and bottom portion 16 of the gasket 12. A middle orcentral cavity 44 for forming the leaf screen 17, and an upper cavity 45for forming the tab means 18 are connected to the lower cavity 43. Theapertures 19 are formed in the leaf screen 17 by elongated pins 46extending upwardly from the lower section 31 of the mold which pins 46are in metal-to-metal contact with the upper section 32 of the mold.

The cavities 43, 44 and 45 communicate with an inlet means or gate 47for receiving a flowable gasket forming material from a nozzle member(not shown). The gasket forming material is introduced through the inletmeans or gate 47 and flows into the upper cavity 45, then into themiddle cavity 44, and finally into the lower cavity 43 completelysurrounding the peripheral edges of the windshield 11. Typically, thegasket forming material is composed of a flowable multi-constituentmaterial such as polyurethane, e.g., composed of a polyol resinconstituent, an isocyanate constituent, and a catalyst, adapted topolymerize and cure in situ on the peripheral portion of the windshield11. The gasket is preferably formed by a reaction injection moldingprocess involving low pressures suitable for use with frangiblesubstrates such as glass. Materials which have been utilized to formsuitable gaskets include Bayflex 110-80 and Bayflex 110-50 manufacturedby Mobay Chemical Corporation of Pittsburgh, Pennsylvania.

As shown in FIG. 4, the mold sections 31 and 32 include facing surfaces39 and 40, respectively, which are in contact with one another outwardlyof the gasket forming cavities, as well as at pins 46, to define aparting line. Since the windshield 11 is relatively fragile, it isimportant to control the amount that the seals 37 and 41 are compressedto avoid fracturing the glass. By enabling the two mold sections to cometogether in metal-to-metal contact, the amount the seals 37 and 41 arecompressed can be controlled. Also, the metal-to-metal contact of themold sections 31 and 32 enables the width of the gasket forming cavities43, 44 and 45 to be precisely controlled.

There is shown in FIG. 5 an alternate embodiment of a window assemblymold according to the present invention. A lower mold section 50 isshown as having an inlet means or gate 1, a lower cavity 52, a middlecavity 53, and an upper cavity 54 which are similar to the inlet means47, the lower cavity 43, the middle cavity 44 and the upper cavity 45 ofthe lower mold section 31 shown in FIG. 3. The mold 50 is utilized toform the gasket in a two step process. A pair of plugs 55 can bepositioned between the lower cavity 52 and the middle cavity 53. FIG. 6is an enlarged fragmentary view of a portion of the mold 50 showing theconnection of the cavities 52 and 53 and the position of one of theplugs 55. FIG. 7 is a fragmentary enlarged sectional view taken alongthe line 7--7 in FIG. 6, but with an upper mold section 57 in place andshowing upper and lower seals 58 and 59, respectively. The plug 55 fitsover the lower edge of the windshield 11 and is preferably formed of aresilient material with a cross section corresponding to that of thecavity 52 so as to completely segregate it from the cavities 53 and 54.

The cavities 53 and 54 can be filled with molding material through theinlet means 51. A second inlet means 60 is connected to the lower cavity52 on the opposite side of the lower mold section 50 from the inletmeans 51. After the cavities 53 and 54 have been filled, the two plugs55 are pulled from the mold and molding material is injected into theinlet means 60 to fill the cavity 52 and integrate that portion of thegasket with the leaf screen and tab means formed by the cavities 53 and54 respectively. In this manner, two different molding materials can beutilized, for example, two different polyurethane formulations with asofter material used around the glass sheet and a harder material usedfor the leaf screen.

Also, a thermoplastic such as polyvinylchloride could be utilized forthe leaf screen. Since this material is not suitable as a gasket, theplugs 55 would be replaced with a plug running the full length of thebottom of the glass sheet 11 to block off that area for later fillingwith a gasket forming material.

Alternatively, the cavity 52 could be filled through the inlet means 60and then the plugs 55 could be pulled before the cavities 53 and 54 arefilled through the inlet means 51. In either case, such an arrangementcould be utilized where it is difficult to obtain a uniform gasket byfilling all three cavities through a single inlet means.

In accordance with the provisions of the patent statutes, the principleand mode of operation of the present invention have been described inwhat has been considered to represent the preferred embodiment. However,it should be understood that the invention may be practiced otherwisethan as specifically illustrated and described without departing fromits spirit or scope.

I claim:
 1. A method of producing a window assembly including at least one transparent sheet having a first gasket member adhered to the peripheral portion thereof and a leaf screen formed as a second gasket member integral with said first gasket member, said first and second gasket members completely encapsulating the peripheral edge of said sheet, said method including the steps of:(a) positioning said sheet of transparent material within the interior of a mold chamber formed by at least two cooperating mold sections; (b) said mold sections provided with a gasket shaping portion which cooperates with a first peripheral portion of the sheet to define a first gasket forming cavity corresponding to a first gasket member to be formed and cooperating with a second peripheral portion of the sheet to define a second gasket forming cavity corresponding to a second gasket member to be formed; (c) injecting into the first and second gasket forming cavities a curable composition, curing said composition in contact with the sheet such that it adheres thereto to produce the first and second gasket members; and (d) removing the window assembly from the mold chamber.
 2. The method according to claim 1 wherein said injected composition is a flowable multi-constituent material which polymerizes and cures in situ in contact with the sheet.
 3. The method according to claim 1 including a step of inserting a plug between said first and second cavities before performing step (c), and performing step (c) by injecting said composition into one of said first and second gasket forming cavities, removing said plug and then injecting said composition into the other one of said first and second gasket forming cavities.
 4. The method according to claim 3 wherein said composition injected into one of said first and second gasket forming cavities is a different material than the composition injected into the other one of said first and second gasket forming cavities. 